1. Field of the Invention
This invention relates to personal mobility vehicles and more particularly to a personal mobility vehicle having a variable wheelbase.
2. Background of the Related Art
The popularity of personal mobility vehicles has dramatically increased over the last serveral decades. This increase in the popularity of personal mobility vehicles is due to many factors including the advent of new structural techniques and materials, as well as a more aging population. Although the population especially in the United States of America is moving towards a more senior age distribution, many of these seniors are very active and mobile. This desire for mobility and activity is present despite physical or health infirmities.
Various types of personal mobility vehicles have been designed and sold in the prior art for different types of applications and activities. When a personal mobility vehicle is used indoor or in confined spaces, the personal mobility vehicle is typically designed with a short wheelbase. The short wheelbase provides a reduced turning radius for the personal mobility vehicle for negotiating smaller confined spaces indoors.
When a personal mobility vehicle is to be used outdoors, a longer wheelbase is desirable. The longer wheelbase provides more stability and a better ride for the personal mobility vehicle.
Some in the prior art have attempted to develop a variable wheelbase personal mobility vehicle for use in both confined spaces and in non-confined spaces. The following U.S. patents are representative of some of the attempts of the prior art to provide a variable wheelbase personal mobility vehicle.
U.S. Pat. No. Re. 33,675 to Young discloses a motorized wheel chair comprising a chassis having two rear wheels and one front wheel mounted thereon. The front wheel is steerable by a handlebar. The rear wheels are driven by an electric motor coupled to a gearbox, for reducing the speed of the wheel chair. The gearbox drives a friction drive assembly that is engageable with the rear wheels and also is coupled to the handlebar such that one of the rear wheels will be disengaged depending upon which direction the handlebar is turned. The device is provided with a switch that cuts power to the device when a change in surface elevation of a desired amount is detected either in front of or behind the device. A second switch may be provided to stop the vehicle upon contact with a foreign object. A third switch may be activated remotely to stop the device. Also, the chassis is adjustable in length, such that as a child grows the device may be adjusted accordingly.
U.S. Pat. No. 3,664,450 to Udden et al. discloses that electrically powered four-wheeled single vehicles especially for disabled persons and invalids and specifically made for out-door use must have such stabilizing qualities that under all circumstances there is no risk for the chair to turn over even if it will have to pass over different kinds of obstacles such as curbs. A further object of such vehicles is to provide a simple and safe steering operation so that the forces from the obstacles to be passed over must not he transmitted to the steering handle, since patients in many cases have considerably reduced power to control such forces by hand. These objects are realized in the invention substantially by the fact that the vehicle comprises a rear and a front portion which are swingably connected to each other by means of telescopic pipes or the like running substantially in parallel with the ground and in the longitudinal direction of the vehicle. To meet the requirement of a safe and unaffected steering operation the front wheels are neutrally positioned in a way that the extension of the swivel axles will cut the contact surfaces between the corresponding wheels and the ground.
U.S. Pat. No. 3,945,449 to Ostrow discloses a generally rectangular shaped support frame provided with ground-engaging wheels upon which almost any type and size of conventional chair may be readily mounted so as to provide mobile means for transporting non-ambulatory persons. Certain of the ground engaging wheels are capable of being rotated manually by the person using the converted wheel chair in order to propel the chair in two embodiments of the invention, electrically in a third embodiment and selectively manually or electrically or both manually and electrically in a fourth embodiment thereof. A retractable foot rest is also incorporated in the support frame.
U.S. Pat. No. 4,351,540 to Minnebraker discloses a wheelchair capable of being constructed in several different sizes from components of standard size in order to permit users of different sizes and users with one or more handicaps to utilize such wheelchairs. The wheelchair includes a main frame and a foot support assembly which can be telescopically adjustably affixed to the main frame. In addition, a seat section can be telescopically adjustably affixed to the main frame such that the seat is located at a selected height and the foot support section can extend outwardly from the frame for a selected distance to accommodate users of differing height. The rear wheels are mounted with respect to the main frame such that the rear wheels can be located in several different positions in order to change the overall center of gravity and the wheelbase of the wheelchair. In this way, the wheelchair can be used for conventional wheelchair movement, as well as for athletic activities. A pair of front wheels are also adjustably mounted with respect to the main frame in order to change the angle of the wheelchair and the seat relative to the ground or other supporting surface.
U.S. Pat. No. 4,452,327 to Mowat et al. discloses a connecting assembly for a light weight vehicle having mutually engaging hook and latch portions. The hook portion comprises engaging hooks to engage and lift the latch means. The engaging portion further includes a shoulder to cause the subsequent disengagement of the latch and engaging portions. Support hooks receive the latch portion upon its disengagement from the engagement hooks. A levered handle causes displacement of the latch portion from the support hooks.
U.S. Pat. No. 4,613,151 to Kielczewski discloses an improved wheelchair adapted to provide enhanced mobility for the occupant together with making ground level activities available. The wheelchair comprises a main frame together with an extension frame telescopically secured to the main frame. A seat is secured to the extension frame so that when the extension frame is moved away from the main frame, the seat is lowered, and when the extension frame is brought back to the main frame, the seat is raised. Means are provided for further enhancing stability in the form of a mechanism to selectively move the drive wheels apart for wider wheel tracking. A rear wheel caster is provided with a selectively operable torsion limiter.
U.S. Pat. No. 4,721,321 to Haury et al. discloses a sports wheelchair including a frame portion having left and right side frame portions. Rear wheel assemblies are connected with the left and right side frame portions such that the rear wheels are connectable to the frame in any one of a plurality of positions and with an adjustable camber. A pair of front wheel assemblies selectively interconnect the front wheels with the frame with any one of a plurality of adjustable heights and positions. An operator supporting seat having a segmented center portion and an outer portion is selectively interconnected with the left and right side frame portions. A folding mechanism enables the left and right side frame portions to be folded together for easier transportation and storage.
U.S. Pat. No. 4,805,925 to Haury et al. discloses a sports wheelchair including a frame portion having left and right side frame portions. Rear wheel assemblies are connected with the left and right side frame portions such that the rear wheels are connectable to the frame in any one of a plurality of positions and with an adjustable camber. A pair of front wheel assemblies selectively interconnect front wheels with the frame with any one of a plurality of adjustable heights and positions. An operator supporting seat having a segmented center portion and an outer portion is selectively interconnected with the left and right side frame portions. A folding mechanism enables the left and right side frame portions to be folded together for easier transportation and storage.
U.S. Pat. No. 4,834,409 to Kramer discloses a personal mobility vehicle main frame unit with front and back ends, both with wheels thereon, a steerable front wheel, a seat and vehicle controls. A pair of spaced rear wheels are mounted at the back end of the vehicle and include moveably mounted axles supporting the rear wheels and connected to arms with mechanisms for selectively angularly moving the axles outwardly and inwardly of the main frame unit to vary wheel base and wheel track. A motor is connected to the wheel support structure for remotely varying the wheel base and wheel track. A separate drive motor is operatively connected to the wheels for movement of the vehicle.
U.S. Pat. No. 4,909,525 to Flowers discloses a personal mobility vehicle comprising front and rear frame sections that can be disassembled and assembled. The frame sections are secured together by a pivotable detachable connection such that the rear frame section is lockingly received in the rear portion of the front frame section and the length of the assembled frame is substantially the same as the length of the front frame section itself. An auxiliary frame section is also provided which can be readily attached to the powered rear frame section to provide improved mobility in those situations in which space for turning is limited.
U.S. Pat. No. 5,094,310 to Richey et al. discloses a powered wheelchair including a high efficiency drive mechanism for increasing the range of travel on a predetermined battery charge. Drive motors are transversely mounted relative to side frames of the wheelchair, and disposed in superimposed arrangement for varying the width of the wheelchair.
U.S. Pat. No. 5,826,670 to Nan discloses a detachable propulsive device for a wheelchair including a longitudinal skeleton frame, a driving unit attached to the front of the skeleton frame, a handle for steering the propulsive device, dimensions adjusting unit, and auxiliary wheels. The dimensions adjusting unit carries four retaining clips and allows to adjust distances between these clips lengthwise and widthwise, so that the clips are capable of engaging and holding side members of the bottom frame of the wheelchair of any desired length and width. The length adjusting mechanism of the dimensions adjusting unit includes a system of telescopically movable hollow tubes with U-shaped cross sliding rails secured to them, while the width adjusting mechanism include s sliding arms carrying the retaining clips on their outer ends and sliding longitudinally along the U-shaped cross sliding rails in the lateral direction. The auxiliary wheels at the rear of the propulsive device are lifted from the ground once the device has been attached to the wheelchair.
U.S. Pat. No. 5,848,658 to Pulver discloses a mid-wheel drive or front wheel drive power wheelchair including a front stabilizer extending from the frame. It includes a first arm pivotally mounted to the frame at a first or upper end and a stabilizer wheel is mounted adjacent a second end. A second arm of the stabilizer assembly is pivotally interconnected between the stabilizer wheel axis and lower end of the shock assembly associated with the suspension arm. The first arm includes a dampening cylinder surrounded by a spring. The spring force preload can be selectively altered and, independently, the height of the stabilizer wheel may be adjusted.
U.S. Pat. No. 5,996,716 to Montiglio et al. discloses a new wheelchair that is adjustable in length, width and height in order to be adapted to different users of different sizes or to a child growing up. The wheelchair comprises T-shaped front and rear frames and a seat assembly. Each T-shaped frame is made of a long arm and two short arms. The rear frame and the front frame are telescopically connected together in such a manner so as to articulate both frames together and to adjust the distance between the front and rear wheels. The two rear wheels are adjustably mounted to the rear frame so that the distance separating the wheels may be adjusted. The seat assembly is mounted on the rear frame and is adjustable in height. The front wheels are mounted on the front frame at each end of the two short arms.
Therefore it is an object of this invention to provide a variable wheelbase personal mobility vehicle that overcomes the inadequacies of the prior art and provides a significant advancement to the personal mobility vehicle art.
Another object of this invention is to provide an improved variable wheelbase personal mobility vehicle capable of varying the wheelbase of the personal mobility vehicle with a variable wheelbase drive mechanism.
Another object of this invention is to provide an improved variable wheelbase personal mobility vehicle that is adaptable to either three wheel or four wheel personal mobility vehicles.
Another object of this invention is to provide an improved variable wheelbase personal mobility vehicle that does not substantially increase the weight of the personal mobility vehicle.
The foregoing has outlined some of the more pertinent objects of the present invention. These objects should be construed as being merely illustrative of some of the more prominent features and applications of the invention. Many other beneficial results can be obtained by applying the disclosed invention in a different manner or modifying the invention within the scope of the invention. Accordingly other objects in a full understanding of the invention may be had by referring to the summary of the invention, the detailed description describing the preferred embodiment in addition to the scope of the invention defined by the claims taken in conjunction with the accompanying drawings.
The present invention is defined by the appended claims with specific embodiments being shown in the attached drawings. For the purpose of summarizing the invention, the invention relates to a variable wheelbase personal mobility vehicle comprising a front wheel assembly and a rear wheel assembly. A front wheel is pivotably mounted relative to the front wheel assembly for controlling the direction of movement of the personal mobility vehicle. Plural drive wheels are mounted relative to the rear wheel assembly for driving the personal mobility vehicle. A seat is connected to the rear frame section for supporting an operator. A variable wheelbase mechanism varies the distance between the front wheel and the plural drive wheels.
In a more specific embodiment of the invention, the front wheel comprises plural front wheels pivotably mounted relative to the front wheel assembly for controlling the direction of movement of the personal mobility vehicle.
In one embodiment of the invention, the variable wheelbase mechanism includes a lock for locking the distance between the front wheel and the plural drive wheels with the lock in a closed condition. The lock enables the distance between the front wheel and the plural drive wheels to be varied with the lock in an open condition.
In another embodiment of the invention, the variable wheelbase mechanism includes a variable wheelbase drive for moving the front wheel relative to the plural rear wheels for changing the wheelbase of the personal mobility vehicle. In one specific example, the variable wheelbase drive comprises a linear actuator. In another specific example, the variable wheelbase drive comprises a jackscrew. In still another specific example, the variable wheelbase drive comprises a scissors jack. In still another specific example, the variable wheelbase drive comprises a rack and pinion mechanism.
In another embodiment of the invention, the variable wheelbase mechanism comprises a slide mechanism for varying the distance between the front wheel and the plurality of rear drive wheels. In one specific example, a slide mechanism interconnects the front wheel assembly to the rear wheel assembly for varying the distance between the front wheel and the plurality of rear drive wheels. In another specific example, the variable wheelbase mechanism comprises a shaft mounted relative either the front or the rear wheel assembly and a shaft receiver mounted relative to the other of the front and rear wheel assembly. The shaft slidably cooperates with the shaft receiver for moving: the front wheel assembly relative to the rear wheel assembly.
The foregoing has outlined rather broadly the more pertinent and important features of the present invention in order that the detailed description that follows may be better understood so that the present contribution to the art can be more fully appreciated. Additional features of the invention will be described hereinafter which form the subject of the claims of the invention. It should be appreciated by those skilled in the art that the conception and the specific embodiments disclosed may be readily utilized as a basis for modifying or designing other structures for carrying out the same purposes of the present invention. It should also be realized by those skilled in the art that such equivalent constructions do not depart from the spirit and scope of the invention as set forth in the appended claims.